WELLINGTON, March 28 (Reuters) - New Zealand's foreign minister Nanaia Mahuta said on Tuesday she had encouraged China to support and strengthen Pacific regional institutions and uphold a 22-year old agreement that sees Pacific countries look after their own security needs.

After returning from Beijing, Mahuta told reporters she had encouraged China to support regional Pacific architecture such as the Pacific Islands Forum, the Forum Fisheries Agency and the Biketawa agreement.

The Biketawa Agreement was signed in 2000 and was a declaration by Pacific leaders for coordinating responses to regional crises such as security issues.

"Again, they registered our view, and it was very much acknowledged that New Zealand has a strong interest in the resilience of the Pacific on all levels," Mahuta said.

New Zealand's tone on security amid China's growing presence in the South Pacific toughened in the past year after China and the Solomon Islands struck a security pact.

New Zealand has consistently expressed concerns about the potential militarisation of the Pacific with China's military buildup in the South China Sea.

Mahuta met with China's top diplomat, Wang Yi, after he returned from a visit to Russia with President Xi Jinping. China is a powerful ally of Russia and both have criticised the U.S. and NATO for undermining global stability.

"Most of the emphasis from the Chinese side was on their efforts to encourage the peace plan that President Xi had put to President Putin," she said.

She added she had clarified what New Zealand would like to see in a peace plan – a withdrawal of Russian troops, a return to internationally agreed boundaries and Ukraine involved in discussions about peace.